Metabotropic Glutamate Receptor Isoxazole Ligands and Their Use as Potentiators 286

ABSTRACT

Compounds in accord with Formula I: 
     
       
         
         
             
             
         
       
     
     wherein R 1 , R 2 , R 3  and R 4  are as defined in the specification, pharmaceutically acceptable salts, methods of making, pharmaceutical compositions containing and methods for using the same.

FIELD OF THE INVENTION

The present invention relates to isoxazole derivatives that function aspotentiators of glutamate receptors, methods for their preparation,pharmaceutical compositions containing them and their use in therapy.

BACKGROUND

The metabotropic glutamate receptors (mGluR) constitute a family ofGTP-binding-protein (G-protein) coupled receptors that are activated byglutamate, and have important roles in synaptic activity in the centralnervous system, including neural plasticity, neural development andneurodegeneration.

Activation of mGluRs in intact mammalian neurons elicits one or more ofthe following responses: activation of phospholipase C; increases inphosphoinositide (PI) hydrolysis; intracellular calcium release;activation of phospholipase D; activation or inhibition of adenylcyclase; increases or decreases in the formation of cyclic adenosinemonophosphate (cAMP); activation of guanylyl cyclase; increases in theformation of cyclic guanosine monophosphate (cGMP); activation ofphospholipase A₂; increases in arachidonic acid release; and increasesor decreases in the activity of voltage- and ligand-gated ion channels(Schoepp et al., 1993, Trends Pharmacol. Sci., 14:13; Schoepp, 1994,Neurochem. Int., 24:439; Pin et al., 1995, Neuropharmacology 34:1; Bordi& Ugolini, 1999, Prog. Neurobiol. 59:55).

Eight mGluR subtypes have been identified, which are divided into threegroups based upon primary sequence similarity, signal transductionlinkages, and pharmacological profile. Group-I includes mGluR1 andmGluR5, which activate phospholipase C and the generation of anintracellular calcium signal. The Group-II (mGluR2 and mGluR3) andGroup-III (mGluR4, mGluR6, mGluR7, and mGluR8) mGluRs mediate aninhibition of adenylyl cyclase activity and cyclic AMP levels. For areview, see Pin et al., 1999, Eur. J. Pharmacol., 375:277-294.

Activity of mGluR family receptors are implicated in a number of normalprocesses in the mammalian CNS, and are important targets for compoundsfor the treatment of a variety of neurological and psychiatricdisorders. Activation of mGluRs is required for induction of hippocampallong-term potentiation and cerebellar long-term depression (Bashir etal., 1993, Nature, 363:347; Bortolotto et al., 1994, Nature, 368:740;Aiba et al., 1994, Cell, 79:365; Aiba et al., 1994, Cell, 79:377). Arole for mGluR activation in nociception and analgesia also has beendemonstrated (Meller et al., 1993, Neuroreport, 4: 879; Bordi & Ugolini,1999, Brain Res., 871:223). In addition, mGluR activation has beensuggested to play a modulatory role in a variety of other normalprocesses including synaptic transmission, neuronal development,apoptotic neuronal death, synaptic plasticity, spatial learning,olfactory memory, central control of cardiac activity, waking, motorcontrol and control of the vestibulo-ocular reflex (Nakanishi, 1994,Neuron, 13:1031; Pin et al., 1995, Neuropharmacology, supra; Knopfel etal., 1995, J. Med. Chem., 38:1417).

Recent advances in the elucidation of the neurophysiological roles ofmGluRs have established these receptors as promising drug targets in thetherapy of acute and chronic neurological and psychiatric disorders andchronic and acute pain disorders. Because of the physiological andpathophysiological significance of the mGluRs, there is a need for newdrugs and compounds that can modulate mGluR function.

DESCRIPTION OF THE INVENTION

We have identified a class of compounds that modulate mGluR function. Inone form the invention provides a compound of Formula I, or apharmaceutically acceptable salt, hydrate, solvate, or enantiomerthereof.

Thus, in one embodiment, the present invention provides a composition ofmatter comprising a compound in accord with Formula I:

wherein:

-   R¹ is selected from C₁₋₃alkyl or halogen;-   R² is selected from C₁₋₃alkyl, C₁₋₃haloalkyl or C₃₋₆cycloalkyl;-   R³ and R⁴ at each occurrence are independently selected from    hydrogen, C₁₋₃alkyl,-   C₁₋₃hydroxyalkyl, C₃₋₆carbocyclyl, heterocyclyl or heteroaryl, or R³    and R⁴ in combination with the nitrogen to which they are attached    form a cyclic moiety selected from morpholino, pyrrolidinyl or    piperazinyl.

In a particular aspect, this embodiment provides compounds wherein R² ismethyl, of Formula I:

or compounds wherein R² is trifluoromethyl or cyclopropyl of Formula II,substantially free of other enantiomers:

wherein:

-   R¹ is selected from methyl or chloro;-   R³ and R⁴ at each occurrence are independently selected from    hydrogen, methyl, isopropyl, 2-hydroxyethyl, cyclopentyl,    cyclohexyl, piperidinyl or pyrazolyl, or R³ and R⁴ in combination    with the nitrogen to which they are attached form a cyclic moiety    selected from morpholino, pyrrolidinyl or piperazinyl.

In another particular aspect, this embodiment provides compounds inaccord with Formula I wherein:

-   R¹ and R² are methyl;-   R³ and R⁴ in combination with the nitrogen to which they are    attached form a cyclic moiety selected from morpholino or    pyrrolidinyl.

In yet another particular aspect, this embodiment provides compounds inaccord with Formula II, substantially free of other enantiomers,wherein:

-   R¹ is chloro;-   R² is trifluoromethyl or cyclopropyl;-   R³ and R⁴ at each occurrence are independently selected from    hydrogen, methyl or isopropyl.

In another aspect, this embodiment provides compounds in accord withFormula II, substantially free of other enantiomers wherein:

-   R¹ is selected from methyl or chloro;-   R² is selected from trifluoromethyl or cyclopropyl;-   R³ is hydrogen or methyl, and-   R⁴ is selected from hydrogen, methyl, cyclopentyl or cyclohexyl.

In particular this embodiment provides the compounds described in theExamples herein as follows:

5-(7-chloro-2-((S)-1-cyclopropylethyl)-1-oxo-2,3-dihydro-1H-isoindolin-5-yl)-N-methylisoxazole-3-carboxamide;

5-(7-chloro-2-((S)-1-cyclopropylethyl)-1-oxo-2,3-dihydro-1H-isoindolin-5-yl)-N,N-dimethylisoxazole-3-carboxamide;

5-[7-Chloro-2-((S)-1-cyclopropyl-ethyl)-1-oxo-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylicacid amide;

5-[2-((S)-1-Cyclopropyl-ethyl)-7-methyl-1-oxo-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylicacid amide;

5-(2-Isopropyl-7-methyl-1-oxo-2,3-dihydro-1H-isoindol-5-yl)-isoxazole-3-carboxylicacid dimethylamide;

5-[2-((S)-1-Cyclopropyl-ethyl)-7-methyl-1-oxo-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylicacid methylamide;

5-[7-Chloro-2-((S)-1-cyclopropyl-ethyl)-1-oxo-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylicacid amide;

5-[2-((S)-1-Cyclopropyl-ethyl)-7-methyl-1-oxo-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylicacid dimethylamide;

7-Chloro-2-isopropyl-5-[3-(pyrrolidine-1-carbonyl)-isoxazol-5-yl]-2,3-dihydro-isoindol-1-one;

5-(7-Chloro-2-isopropyl-1-oxo-2,3-dihydro-1H-isoindol-5-yl)-isoxazole-3-carboxylicacid (2-hydroxy-ethyl)-methyl-amide;

5-[7-Methyl-1-oxo-2-((S)-2,2,2-trifluoro-1-methyl-ethyl)-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylicacid dimethylamide;

5-[2-((S)-1-Cyclopropyl-ethyl)-7-methyl-1-oxo-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylicacid isopropyl-methyl-amide;

5-[2-((S)-1-Cyclopropyl-ethyl)-7-methyl-1-oxo-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylicacid (2-hydroxy-ethyl)-methyl-amide;

5-(7-Chloro-2-isopropyl-1-oxo-2,3-dihydro-1H-isoindol-5-yl)-isoxazole-3-carboxylicacid cyclopentylamide;

7-Chloro-2-isopropyl-5-[3-(morpholine-4-carbonyl)-isoxazol-5-yl]-2,3-dihydro-isoindol-1-one;

2-((S)-1-Cyclopropyl-ethyl)-7-methyl-5-[3-(piperazine-1-carbonyl)-isoxazol-5-yl]-2,3-dihydro-isoindol-1-one;

5-[7-Chloro-1-oxo-2-((S)-2,2,2-trifluoro-1-methyl-ethyl)-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylicacid dimethylamide;

5-[7-Chloro-2-((S)-1-cyclopropyl-ethyl)-1-oxo-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylicacid isopropyl-methyl-amide;

5-[7-Chloro-2-((S)-1-cyclopropyl-ethyl)-1-oxo-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylicacid (2-hydroxy-ethyl)-methyl-amide;

7-Chloro-2-((S)-1-cyclopropyl-ethyl)-5-[3-(morpholine-4-carbonyl)-isoxazol-5-yl]-2,3-dihydro-isoindol-1-one,and

7-Chloro-5-[3-(morpholine-4-carbonyl)-isoxazol-5-yl]-2-((S)-2,2,2-trifluoro-1-methyl-ethyl)-2,3-dihydro-isoindol-1-one.

Also provided are processes for making compounds of Formula I or FormulaII.

Further provided are pharmaceutical compositions comprising a compoundaccording to Formula I or Formula II together with a pharmaceuticallyacceptable carrier or excipient.

In another embodiment, a method for the treatment or prevention ofneurological and psychiatric disorders associated with glutamatedysfunction in an animal in need of such treatment is provided. Themethod comprises a step of administering to the animal a therapeuticallyeffective amount of a compound of Formula I or Formula II, or apharmaceutical composition comprising such an amount.

The invention also provides for the use of a compound according toFormula I or II, or a pharmaceutically acceptable salt or solvatethereof, in the manufacture of a medicament for the treatment ofconditions mentioned herein.

Further, the invention provides a compound of Formula I or II, or apharmaceutically acceptable salt or solvate thereof, for use in therapy.

Compounds described herein exhibit activity as modulators ofmetabotropic glutamate receptors and more particularly exhibit activityas potentiators of the mGluR2 receptor. It is contemplated that thecompounds will be useful in therapy as pharmaceuticals, in particularfor the treatment of neurological and psychiatric disorders associatedwith glutamate dysfunction.

Definitions

Unless described otherwise within this specification, the nomenclatureused in this specification generally follows the examples and rulesstated in Nomenclature of Organic Chemistry, Sections A, B, C, D, E, Fand H, Pergamon Press, Oxford, 1979, which is incorporated by referencesherein for its exemplary chemical structure names and rules on namingchemical structures. Optionally, a name of a compound may be generatedusing a chemical naming program: ACD/ChemSketch, Version 5.09/September2001, Advanced Chemistry Development, Inc., Toronto, Canada.

The term “C₁₋₃alkyl” as used herein means a straight-, branched-chain orcyclic hydrocarbon radical having from one to three carbon atoms, andincludes methyl, ethyl, propyl, isopropyl, and cyclopropyl.

The term “C₁₋₃haloalkoxyl” as used herein means a straight- orbranched-chain alkoxy radical having from one to three carbon atoms andat least one halo substituent and includes fluoromethoxyl,trifluoromethoxyl, fluoroethoxyl, trifluoropropyloxyl,fluoroisopropyloxy and the like.

The term “halo” as used herein means halogen and includes fluoro,chloro, bromo, iodo, in both radioactive and non-radioactive forms.

The symbol Δ when used herein means heating or the application of heat.

The term “pharmaceutically acceptable salt” means either an acidicaddition salt or a basic addition salt that is compatible with theadministration to patients.

A “pharmaceutically acceptable acidic addition salt” is any non-toxicorganic or inorganic acidic addition salt of a compound represented byFormula I. Illustrative inorganic acids that form suitable salts includehydrochloric, hydrobromic, sulfuric and phosphoric acid and acid metalsalts such as sodium monohydrogen orthophosphate and potassium hydrogensulfate. Illustrative organic acids that form suitable salts include themono-, di- and tricarboxylic acids. Illustrative of such acids are, forexample, acetic, glycolic, lactic, pyruvic, malonic, succinic, glutaric,fumaric, malic, tartaric, citric, ascorbic, maleic, hydroxymaleic,benzoic, hydroxybenzoic, phenylacetic, cinnamic, salicylic,2-phenoxybenzoic, p-toluenesulfonic acid and other sulfonic acids suchas methanesulfonic acid and 2-hydroxyethanesulfonic acid. Wherechemically feasible, mono- or di-acid salts can be formed and such saltscan exist in either a hydrated solvated or substantially anhydrous form.In general, the acidic addition salts of these compounds are moresoluble in water and various hydrophilic organic solvents and generallydemonstrate higher melting points in comparison to their free baseforms. Other salts, e.g. oxalates, may be used, for example in theisolation of compounds of Formula I for laboratory use or for subsequentconversion to a pharmaceutically acceptable acidic addition salt.

“Solvate” means a compound of Formula I or the pharmaceuticallyacceptable salt of a compound of Formula I wherein molecules of asuitable solvent are incorporated in a crystal lattice. A suitablesolvent is physiologically tolerable at the dosage administered as thesolvate. Examples of suitable solvents are ethanol, water and the like.When water is the solvent, the molecule is referred to as a hydrate.

The term “stereoisomers” is a general term for all isomers of theindividual molecules that differ only in the orientation of their atomsin space. It includes mirror image isomers (enantiomers), geometric(cis/trans) isomers and isomers of compounds with more than one chiralcentre that are not mirror images of one another (diastereomers).

The term “treat” or “treating” means to alleviate symptoms, eliminatethe causation of the symptoms either on a temporary or permanent basis,or to prevent or slow the appearance of symptoms of the named disorderor condition.

The term “therapeutically effective amount” means an amount of thecompound that is effective in treating the named disorder or condition.

The term “pharmaceutically acceptable carrier” means a non-toxicsolvent, dispersant, excipient, adjuvant or other material that is mixedwith the active ingredient in order to permit the formation of apharmaceutical composition, i.e., a dosage form capable ofadministration to the patient. One example of such a carrier is apharmaceutically acceptable oil typically used for parenteraladministration.

A pharmaceutically acceptable salt, hydrate, solvate, or combinationthereof of each of the mentioned embodiments is contemplated to bewithin the scope of the invention.

The optically active forms of the compound of the invention may beprepared, for example, by chiral chromatographic separation of aracemate, by synthesis from optically active starting materials or byasymmetric synthesis.

It will also be understood by those of skill in the art that certaincompounds of the present invention may exist in a solvated, for examplehydrated, as well as an unsolvated form. It will further be understoodthat the present invention encompasses all such solvated forms of thecompounds of Formula I or Formula II.

Within the scope of the invention are also salts of the compounds ofFormula I or Formula II. Generally, pharmaceutically acceptable salts ofcompounds of the present invention are obtained using standardprocedures well known in the art.

In one embodiment of the present invention, a compound of Formula I orFormula II may be converted to a pharmaceutically acceptable salt orsolvate thereof, such as a hydrochloride, hydrobromide, phosphate,acetate, fumarate, maleate, tartrate, citrate, methanesulphonate orp-toluenesulphonate.

Processes for Preparing Compounds

Compounds according to Formula I may generally be prepared by thesynthetic processes illustrated herein. The choice of particularstructural features and/or substituents may influence the selection ofone process over another and may influence the conditions under whichthe process is carried out.

Within these general guidelines, processes described herein can be usedto prepare exemplary compounds of this invention. Unless indicatedotherwise, the variables in the described schemes and processes have thesame definitions as those given for Formulae I and II herein. Also foravoidance of doubt, in general when Formula I is referred to it will beunderstood to encompass compounds of Formula II.

A person of ordinary skill in the art thus will appreciate that othercompounds in accord with Formula I may be made by variations andadditions adapting one or more of the processes disclosed herein.

The invention is further illustrated by way of the examples herein,which describe several embodiments of the invention. The syntheticscheme and the synthetic procedures provided for Examples 1 and 2 areprovided by way of illustration and are not to be construed as limitingthe invention. It will be clear to those skilled in the art thatcompounds other than those illustrated may be readily prepared byprocesses analogous to those described.

General Methods

Starting materials are commercially available or are described in theliterature.

¹H and ¹³C NMR spectra were recorded either on Bruker 300, Bruker DPX400or Varian +400 spectrometers operating at 300, 400 and 500 MHz for ¹HNMR respectively, using TMS or the residual solvent signal as reference,in deuterated chloroform as solvent unless otherwise indicated. Allreported chemical shifts are in ppm on the delta-scale, and the finesplitting of the signals as appearing in the recordings (s: singlet, brs: broad singlet, d: doublet, t: triplet, q: quartet, m: multiplet).

Analytical in-line liquid chromatography separations followed by massspectra detections, were recorded on a Waters LCMS consisting of anAlliance 2795 (LC) and a ZQ single quadrapole mass spectrometer. Themass spectrometer was equipped with an electrospray ion source operatedin a positive and/or negative ion mode. The ion spray voltage was ±3 kVand the mass spectrometer was scanned from m/z 100-700 at a scan time of0.8 s. To the column, X-Terra MS, Waters, C8, 2.1×50 mm, 3.5 mm, wasapplied a linear gradient from 5% to 100% acetonitrile in 10 mM ammoniumacetate (aq.), or in 0.05 to 0.1% formic acid (aq.).

Purification of products was done using Silicycle SilicaFlash Catridges(cat #FLH-R10030B) on an ISCO automated flash chromatography system, orby flash chromatography in silica-filled glass columns.

Microwave heating was performed in an Emrys Optimizer Single-modemicrowave cavity producing continuous irradiation at 2450 MHz (PersonalChemistry AB, Uppsala, Sweden).

LC-MS HPLC Conditions:

-   Method A: Column: Waters Acquity UPLC BEH-C18, 1.7 μm, 2.1 mm ID×50    mm Flow: 1.0 mL/min. Gradient: 95% A to 95% B over 0.9 minutes hold    0.3 minutes ramp down to 95% A over 0.1 minute following a standard    linear gradient. Where A=2% acetonitrile in water with 0.1% formic    acid and B=2% water in acetonitrile with 0.05% formic acid. UV-DAD    210-400 nm.-   Method B: Column: Agilent Zorbax SB-C8, 5 μm, 2.1 mm ID×50 mm Flow:    1.4 mL/min, Gradient: 95% A to 90% B over 3 minutes hold 1 minute    ramp down to 95% A over 1 minute and hold 1 minute following a    standard linear gradient. Where A=2% acetonitrile in water with 0.1%    formic acid and B=2% water in acetonitrile with 0.05% formic acid.    UV-DAD 210-400 nm.

The instruments, methods and conditions described herein are provided byway of illustration and are not to be construed as limiting theinvention. Those of skill in the art will appreciate that otherinstruments and methods may be used to make the measurements or achievethe separations described.

Synthetic Processes:

Scheme 1 illustrates a representative synthesis of a 6-substituted4-bromo-2-bromomethyl-benzoic acid methyl ester from commerciallyavailable precursors wherein the respective reaction steps comprise asfollows: (a) NaNO₂, aq. HCl; (b) NaCN, CuCN and HCl; (c) NaOH; (d)nitrososulphuric acid; (e) MeI and K₂CO₃, and (f) NBS and (PhCO₂)₂.Briefly, a 4-bromo-aniline may be diazotized under Sandmeyer reactionconditions, followed by conversion to the nitrile using sodium cyanideand copper cyanide. The nitrile may then be hydrolyzed to an amide bybasic hydrolysis. The amide can then be hydrolyzed with nitrososulphuricacid to provide a benzoic acid, which may be converted to a methyl esterunder standard conditions. The benzylic methyl group may bemonobrominated with N-bromosuccinimide using benzoyl peroxide as aradical initiator to yield a desired 6-substituted4-bromo-2-bromomethyl-benzoic acid methyl ester.

A 6-substituted 4-bromo-2-bromomethyl-benzoic acid methyl ester may becyclized to an isoindolone with an amine, or a chiral amine if a chiralcompound is desired, (g) CH₃CHR²NH₂, K₂CO₃, B(OH)₃, as shown in Scheme2.

A compound of Formula I (or Formula II) may be prepared from anisoindolone by a series of reactions steps as shown in Scheme 3, asfollows: (h) Pd(BnCN)₂Cl₂, TMS-≡, Cu(OAc)₂, PPh₃ in diisopropyl amineunder gentle heating for 2 hrs; (i) KOH, EtOH/H₂O, 1 Hr at RT; (j) ethyl2-chloro-2-(hydroxyimino)acetate, KHCO₃, EA/H₂O, 16 Hr at RT and (k)NaOH, MeOH/H₂O, 1 Hr at RT, followed by (l) IBCF, NMM, R³R⁴NH in THF at−20° C. Briefly, a 4-bromo-isoindolone may be reacted under Sonagashiraconditions with a protected acetylene. Deprotection of the acetylenewith base, followed by reaction with ethyl2-chloro-2-(hydroxyimino)acetate will generate an isoxazole ester.Finally, hydrolysis of the ester to the acid and amidation usingisobutylchloroformate, N-methyl morpholine and an appropriate amine,will generate a desired amide. Alternatively, an amide can be generatedvia an isoxazole ester directly by step (m) by reaction with an amine,R³R⁴NH in ethanol, and heating.

EXAMPLES Example 1

-   5-(7-chloro-2-((S)-1-cyclopropylethyl)-1-oxo-2,3-dihydro-1H-isoindolin-5-yl)-N,N-dimethylisoxazole-3-carboxamide

A solution of ethyl5-(7-chloro-2-((S)-1-cyclopropylethyl)-1-oxoisoindolin-5-yl)isoxazole-3-carboxylate(29.59 g, 78.94 mmol) in ethanol (500 mL) was treated with a 33%solution of ethanolic dimethylamine (352 mL, 1973.6 mmol). The resultinglight-green solution was gently warmed for approximately 3 hours, withsufficient heating to maintain a clear solution (approximately 50° C.).The reaction was cooled to room temperature and the volatiles removedunder reduced pressure. The material was purified by flashchromatography on silica gel eluting with a gradient of 0 to 50% ethylacetate in methylene chloride to afford the desired compound. Theisolated product was then subjected to an additional purification stepby crystallization in ethanol. The5-(7-chloro-2-((S)-1-cyclopropylethyl)-1-oxoisoindolin-5-yl)-N,N-dimethylisoxazole-3-carboxamide(34.88 g, 93.30 mmol) was taken up in approximately 350 mL of ethanoland warmed to 70-80° C. until all of the product dissolved. The solutionwas quickly filtered through a medium glass frit, warmed back up to70-80° C. and filtered through a paper filter (Whatman #1). The filtratewas heated again to 70-80° C. to assure a clear solution and allowed toslowly cool to room temperature (the final volume of solvent was 450mL). After sitting overnight, fine crystals of the title product formed.The mixture was cooled in a refrigerator for an additional 2 hours. Thecrystals were isolated by filtration, washed with cold ethanol and driedunder high vacuum at room temperature to afford white, small needle-likecrystals (27.21 g, 78%). Mp 143.5° C. ¹H NMR (300 MHz, DMSO-d₆) δ ppm0.21-0.32 (m, 1H) 0.35-0.50 (m, 2H) 0.53-0.67 (m, 1H) 1.16 (dd, 1H) 1.30(d, 3H) 3.06 (s, 3H) 3.14 (s, 3H) 3.59 (dd, 1H) 4.62 (s, 2H) 7.50 (s,1H) 8.06 (s, 1H) 8.11 (s, 1H). MS ESI, m/z=374 (M+H). HPLC Method B:0.70 min.

Intermediate compounds were prepared as follows:

a) Ethyl5-(7-chloro-2-((S)-1-cyclopropylethyl)-1-oxoisoindolin-5-yl)isoxazole-3-carboxylate

7-chloro-2-((S)-1-cyclopropylethyl)-5-ethynylisoindolin-1-one (28.66 g,110.35 mmol) and potassium hydrogen carbonate (110.0 g, 1103.45 mmol)were dissolved in a solution consisting of 1200 mL of ethyl acetate and400 mL of water. To this solution was added ethyl2-chloro-2-(hydroxyimino)acetate (66.9 g, 441.38 mmol). The ethyl2-chloro-2-(hydroxyimino)acetate was added at room temperature as asolution in 160 mL of ethyl acetate via syringe pump at a rate of 5mL/Hr. Following the addition of the ethyl 2-chloro-2(hydroxyimino)acetate, the reaction was allowed to continue stirring atroom temperature for an additional 12 hours. The ethyl acetate layer wasextracted in a separatory funnel, dried over magnesium sulfate, filteredand concentrated under reduced pressure. The material was purified byflash chromatography on silica gel eluting with a gradient of 0 to 25%ethyl acetate in hexane to afford the title compound as a white solid(17.05 g, 41.2%). ¹H NMR (300 MHz, CDCl₃) δ ppm 0.36-0.53 (m, 3H)0.63-0.73 (m, 1H) 0.98-1.12 (m, 1H) 1.38 (d, 3H) 1.47 (t, 3H) 3.80 (dq,1H) 4.43-4.65 (m, 4H) 7.05 (s, 1H) 7.83 (s, 2H). MS ESI, m/z=375 (M+H).HPLC Method B: 0.82 min

b) 7-chloro-2-((S)-1-cyclopropylethyl)-5-ethynylisoindolin-1-one

7-chloro-2-((S)-1-cyclopropylethyl)-5-(2-(trimethylsilyl)ethynyl)isoindolin-1-one(40.88 g, 123.17 mmol) was dissolved in 250 mL of ethanol and stirred atroom temperature. To the reaction mixture was added a solution ofpotassium hydroxide (0.10 g, 1.85 mmol) in 20 mL of water. The reactionimmediately turned black and was allowed to continue stirring for 90minutes at room temperature. The volatiles were removed under reducedpressure and the product purified by flash chromatography on silica geleluting with a gradient of 0 to 40% ethyl acetate in hexane. Thisafforded the desired product as a light tan solid (20.75 g, 69.7%). ¹HNMR (300 MHz, CDCl₃) δ ppm 0.34-0.50 (m, 3H) 0.58-0.69 (m, 1H) 0.93-1.07(m, 1H) 1.34 (d, 3H) 3.22 (s, 1H) 3.76 (dq, 1H) 4.31-4.54 (m, 2H) 7.45(s, 1H) 7.51 (s, 1H). MS ESI m/z=260 (M+H). HPLC Method B: 0.80 min.

c)7-chloro-2-((S)-1-cyclopropylethyl)-5-(2-(trimethylsilyl)ethynyl)isoindolin-1-one

5-bromo-7-chloro-2-((S)-1-cyclopropylethyl)isoindolin-1-one (5.0 g,15.89 mmol) was placed in a 3-neck flask, fitted with an internalthermocouple and dissolved in 150 mL of degassed diisopropyl amine. Tothis solution was added copper (II) acetate (0.14 g, 0.79 mmol),triphenylphosphine (0.417 g, 1.59 mmol) andbis(benzonitrile)dichloropalladium (II) (0.30 g, 0.79 mmol). Finally,ethynyltrimethylsilane (4.84 mL, 34.96 mmol) was added dropwise over a20-min period. After the addition of the silane was complete, thereaction mixture was heated to and held at 65° C. until startingmaterial was consumed (as monitored by LC/MS). The reaction was allowedto cool to room temperature and the volatiles were removed under reducedpressure. The material was then filtered through a glass frit and theremaining solids in the frit were rinsed with diethyl ether. Thevolatiles were again removed under reduced pressure and the concentratedresidue was purified by flash chromatography on silica gel eluting with0 to 40% ethyl acetate in hexane. This afforded the title compound as atan solid (4.90 g, 93%). ¹H NMR (300 MHz, CDCl₃) δ ppm 0.18-0.22 (m, 9H)0.29-0.43 (m, 3H) 0.53-0.62 (m, 1H) 0.88-1.01 (m, 1H) 1.27 (d, 3H) 3.69(dq, 1H) 4.33 (q, 2H) 7.35 (d, 1H) 7.42 (s, 1H). MS ESI m/z=332 (M+H).HPLC Method A: 1.05 min.

Example 2

-   5-(7-chloro-2-((S)-1-cyclopropylethyl)-1-oxo-2,3-dihydro-1H-isoindolin-5-yl)-N-methylisoxazole-3-carboxamide

Ethyl5-(7-chloro-2-((S)-1-cyclopropylethyl)-1-oxoisoindolin-5-yl)isoxazole-3-carboxylate(4.00 g, 10.67 mmol) was placed into a 200 mL pressure vessel followedby the addition of ethanol (20 mL) and a 33% solution of ethanolicmethylamine (57.2 mL, 320.16 mmol). The solution was warmed to and heldat 55° C. for 10 minutes and then cooled to room temperature. Aprecipitate formed, was collected by filtration and dried overnight in a40° C. vacuum oven. Residual ethanol was removed from the isolatedproduct by dissolving the solids in a minimal amount of methylenechloride followed by removal of the volatiles under reduced pressure toafford the title compound (3.46 g, 90%), Mp 212.3° C. ¹H NMR (300 MHz,CDCl₃) δ ppm 0.28-0.46 (m, 3H) 0.54-0.64 (m, 1H) 0.90-1.02 (m, 1H) 1.30(d, 3H) 2.98 (d, 3H) 3.64-3.80 (m, 1H) 4.35-4.57 (m, 2H) 6.76 (d, 1H)7.00 (s, 1H) 7.69 (s, 1H) 7.75 (s, 1H). MS APCI, m/z=360 (M+H). HPLCMethod B: 2.19 min.

The compounds of Examples 3 to 21 illustrated in Table 1 weresynthesized in accord with the processes described herein by the use ofsuitable intermediates.

Example 3

-   5-[7-Chloro-2-((S)-1-cyclopropyl-ethyl)-1-oxo-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylic    acid amide.

Example 4

-   5-[2-((S)-1-Cyclopropyl-ethyl)-7-methyl-1-oxo-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylic    acid amide

Example 5

-   5-(2-Isopropyl-7-methyl-1-oxo-2,3-dihydro-1H-isoindol-5-yl)-isoxazole-3-carboxylic    acid dimethylamide.

Example 6

-   5-[2-((S)-1-Cyclopropyl-ethyl)-7-methyl-1-oxo-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylic    acid methylamide.

Example 7

-   5-[7-Chloro-2-((S)-1-cyclopropyl-ethyl)-1-oxo-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylic    acid amide.

Example 8

-   5-[2-((S)-1-Cyclopropyl-ethyl)-7-methyl-1-oxo-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylic    acid dimethylamide.

Example 9

-   7-Chloro-2-isopropyl-5-[3-(pyrrolidine-1-carbonyl)-isoxazol-5-yl]-2,3-dihydro-isoindol-1-one.

Example 10

-   5-(7-Chloro-2-isopropyl-1-oxo-2,3-dihydro-1H-isoindol-5-yl)-isoxazole-3-carboxylic    acid (2-hydroxy-ethyl)-methyl-amide.

Example 11

-   5-[7-Methyl-1-oxo-2-((S)-2,2,2-trifluoro-1-methyl-ethyl)-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylic    acid dimethylamide.

Example 12

-   5-[2-((S)-1-Cyclopropyl-ethyl)-7-methyl-1-oxo-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylic    acid isopropyl-methyl-amide.

Example 13

-   5-[2-((S)-1-Cyclopropyl-ethyl)-7-methyl-1-oxo-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylic    acid (2-hydroxy-ethyl)-methyl-amide.

Example 14

-   5-(7-Chloro-2-isopropyl-1-oxo-2,3-dihydro-1H-isoindol-5-yl)-isoxazole-3-carboxylic    acid cyclopentylamide.

Example 15

-   7-Chloro-2-isopropyl-5-[3-(morpholine-4-carbonyl)-isoxazol-5-yl]-2,3-dihydro-isoindol-1-one.

Example 16

-   2-((S)-1-Cyclopropyl-ethyl)-7-methyl-5-[3-(piperazine-1-carbonyl)-isoxazol-5-yl]-2,3-dihydro-isoindol-1-one.

Example 17

-   5-[7-Chloro-1-oxo-2-((S)-2,2,2-trifluoro-1-methyl-ethyl)-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylic    acid dimethylamide.

Example 18

-   5-[7-Chloro-2-((S)-1-cyclopropyl-ethyl)-1-oxo-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylic    acid isopropyl-methyl-amide.

Example 19

-   5-[7-Chloro-2-((S)-1-cyclopropyl-ethyl)-1-oxo-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylic    acid (2-hydroxy-ethyl)-methyl-amide.

Example 20

-   7-Chloro-2-((S)-1-cyclopropyl-ethyl)-5-[3-(morpholine-4-carbonyl)-isoxazol-5-yl]-2,3-dihydro-isoindol-1-one

Example 21

-   7-Chloro-5-[3-(morpholine-4-carbonyl)-isoxazol-5-yl]-2-((S)-2,2,2-trifluoro-1-methyl-ethyl)-2,3-dihydro-isoindol-1-one.

TABLE 1 Example RT No. Structure MW M + H (HPLC) 1

373.8 374.2 0.70 2

359.8 360.1 2.19 3

319.7 320.0 1.91 4

325.4 326.1 2.21 5

327.4 328.4 2.19 6

339.4 340.1 2.30 7

345.8 346.0 2.10 8

353.4 354.4 2.29 9

373.8 374.0 2.32 10

377.8 378.0 1.87 11

381.4 382.0 2.40 12

381.5 328.3 2.58 13

383.4 384.2 2.12 14

387.9 388.1 2.50 15

389.8 390.0 2.12 16

394.5 395.2 1.77 17

401.8 402.0 2.36 18

401.9 402.3 2.53 19

403.9 384.2 2.05 20

415.9 416.1 2.31 21

443.8 444.0 2.36 MW is calculated molecular weight M + H is mass asmeasured RT is retention time in HPLC in minutes. Method A was used forExample 1 and Method B for Examples 2 through 21 inclusive.

Pharmaceutical Compositions

The compounds described herein may be generally formulated into apharmaceutical composition comprising a compound of Formula I or apharmaceutically acceptable salt or solvate thereof, in association witha pharmaceutically acceptable carrier or excipient. The pharmaceuticallyacceptable carriers can be either solid or liquid. Solid formpreparations include, but are not limited to, powders, tablets,dispersible granules, capsules, cachets, and suppositories.

A solid carrier can be one or more substance, which may also act asdiluents, flavoring agents, solubilizers, lubricants, suspending agents,binders or table disintegrating agents. A solid carrier can also be anencapsulating material.

In powders, the carrier is a finely divided solid, which is in a mixturewith the finely divided compound active component. In tablets, theactive component is mixed with the carrier having the necessary bindingproperties in suitable proportions and compacted in the shape and sizedesired.

For preparing suppository compositions, a low-melting wax such as amixture of fatty acid glycerides and cocoa butter is first melted andthe active ingredient is dispersed therein by, for example, stirring.The molten homogeneous mixture is then poured into convenient sizedmoulds and allowed to cool and solidify.

Suitable carriers include, but are not limited to, magnesium carbonate,magnesium stearate, talc, lactose, sugar, pectin, dextrin, starch,tragacanth, methyl cellulose, sodium carboxymethyl cellulose,low-melting wax, cocoa butter, and the like.

The term composition is also intended to include the formulation of theactive component with encapsulating material as a carrier providing acapsule in which the active component (with or without other carriers)is surrounded by a carrier which is thus in association with it.Similarly, cachets are included.

Tablets, powders, cachets, and capsules can be made as solid dosageforms suitable for oral administration.

Liquid form compositions include solutions, suspensions, and emulsions.For example, sterile water or water propylene glycol solutions of theactive compounds may be liquid preparations suitable for parenteraladministration. Liquid compositions can also be formulated in solutionin aqueous polyethylene glycol solution.

Aqueous solutions for oral administration can be prepared by dissolvingthe active component in water and adding suitable colorants, flavoringagents, stabilizers, and thickening agents as desired. Aqueoussuspensions for oral use can be made by dispersing the finely dividedactive component in water together with a viscous material such asnatural synthetic gums, resins, methyl cellulose, sodium carboxymethylcellulose, and other suspending agents known to the pharmaceuticalformulation art. Exemplary compositions intended for oral use maycontain one or more coloring, sweetening, flavoring and/or preservativeagents.

Depending on the mode of administration, the pharmaceutical compositionwill include from about 0.05% w (percent by weight) to about 99% w, moreparticularly, from about 0.10% w to 50% w, of the compound of theinvention, all percentages by weight being based on the total weight ofthe composition.

A therapeutically effective amount for the practice of the presentinvention can be determined by one of ordinary skill in the art usingknown criteria including the age, weight and response of the individualpatient, and interpreted within the context of the disease that is beingtreated or being prevented.

Medical Uses

Compounds described herein exhibit activity as modulators ofmetabotropic glutamate receptors and more particularly exhibit activityas potentiators of the mGluR2 receptor. It is contemplated that thecompounds will be useful in therapy as pharmaceuticals, in particularfor the treatment of neurological and psychiatric disorders associatedwith glutamate dysfunction in an animal and particularly in a human.

More specifically, the neurological and psychiatric disorders include,but are not limited to, disorders such as cerebral deficit subsequent tocardiac bypass surgery and grafting, stroke, cerebral ischemia, spinalcord trauma, head trauma, perinatal hypoxia, cardiac arrest,hypoglycemic neuronal damage, dementia (including AIDS-induceddementia), Alzheimer's disease, Huntington's Chorea, amyotrophic lateralsclerosis, ocular damage, retinopathy, cognitive disorders, idiopathicand drug-induced Parkinson's disease, muscular spasms and disordersassociated with muscular spasticity including tremors, epilepsy,convulsions, cerebral deficits secondary to prolonged statusepilepticus, migraine (including migraine headache), urinaryincontinence, substance tolerance, substance withdrawal (including,substances such as opiates, nicotine, tobacco products, alcohol,benzodiazepines, cocaine, sedatives, hypnotics, etc.), psychosis,schizophrenia, anxiety (including generalized anxiety disorder, panicdisorder, social phobia, obsessive compulsive disorder, andpost-traumatic stress disorder (PTSD)), mood disorders (includingdepression, mania, bipolar disorders), circadian rhythm disorders(including jet lag and shift work), trigeminal neuralgia, hearing loss,tinnitus, macular degeneration of the eye, emesis, brain edema, pain(including acute and chronic pain states, severe pain, intractable pain,neuropathic pain, inflammatory pain, and post-traumatic pain), tardivedyskinesia, sleep disorders (including narcolepsy), attentiondeficit/hyperactivity disorder, and conduct disorder.

The invention thus provides a use of any of the compounds according toFormula I, or a pharmaceutically acceptable salt or solvate thereof, forthe manufacture of a medicament for the treatment of any of theconditions discussed above.

Additionally, the invention provides a method for the treatment of asubject suffering from any of the conditions discussed above, whereby aneffective amount of a compound according to Formula I or apharmaceutically acceptable salt or solvate thereof, is administered toa patient in need of such treatment. The invention also provides acompound of Formula I or pharmaceutically acceptable salt or solvatethereof, as hereinbefore defined for use in therapy.

In the context of the present specification, the term “therapy” alsoincludes “prophylaxis” unless there are specific indications to thecontrary. The term “therapeutic” and “therapeutically” should beconstrued accordingly. The term “therapy” within the context of thepresent invention further encompasses the administration of an effectiveamount of a compound of the present invention, to mitigate either apre-existing disease state, acute or chronic, or to mitigate a recurringcondition. This definition also encompasses prophylactic therapies forprevention of recurring conditions and continued therapy for chronicdisorders.

In use for therapy in a warm-blooded animal such as a human, thecompounds of the present invention may be administered in the form of aconventional pharmaceutical composition by any route including orally,intramuscularly, subcutaneously, topically, intranasally,intraperitoneally, intrathoracically, intravenously, epidurally,intrathecally, intracerebroventricularly and by injection into thejoints. In preferred embodiments of the invention, the route ofadministration is oral, intravenous, or intramuscular.

The dosage will depend on the route of administration, the severity ofthe disease, age and weight of the patient and other factors normallyconsidered by the attending physician, who determines the individualregimen and dosage level for a particular patient.

As mentioned above, the compounds described herein may be provided ordelivered in a form suitable for oral use, for example, in a tablet,lozenge, hard and soft capsule, aqueous solution, oily solution,emulsion, and suspension. Alternatively, the compounds may be formulatedinto a topical administration, for example, as a cream, ointment, gel,spray, or aqueous solution, oily solution, emulsion or suspension. Thecompounds described herein also may be provided in a form that issuitable for nasal administration, for example, as a nasal spray, nasaldrops, or dry powder. The compounds can be administered to the vagina orrectum in the form of a suppository. The compounds described herein alsomay be administered parentally, for example, by intravenous,intravesicular, subcutaneous, or intramuscular injection or infusion.The compounds can be administered by insufflation (for example as afinely divided powder). The compounds may also be administeredtransdermally or sublingually.

In addition to their use in therapeutic medicine, the compounds ofFormula I, or salts thereof, are useful as pharmacological tools in thedevelopment and standardization of in vitro and in vivo test systems forthe evaluation of the effects of inhibitors of mGluR-related activity inlaboratory animals as part of the search for new therapeutics agents.Such animals include, for example, cats, dogs, rabbits, monkeys, ratsand mice.

A compound of Formula I or a pharmaceutically acceptable salt, solvateor in vivo hydrolysable ester thereof, or a pharmaceutical compositionor formulation comprising a compound of Formula I may be administeredconcurrently, simultaneously, sequentially or separately with anotherpharmaceutically active compound or compounds selected from thefollowing:

-   (i) antidepressants such as amitriptyline, amoxapine, bupropion,    citalopram, clomipramine, desipramine, doxepin duloxetine,    elzasonan, escitalopram, fluvoxamine, fluoxetine, gepirone,    imipramine, ipsapirone, maprotiline, nortriptyline, nefazodone,    paroxetine, phenelzine, protriptyline, reboxetine, robalzotan,    sertraline, sibutramine, thionisoxetine, tranylcypromaine,    trazodone, trimipramine, venlafaxine and equivalents and    pharmaceutically active isomer(s) and metabolite(s) thereof;-   (ii) atypical antipsychotics including for example quetiapine and    pharmaceutically active isomer(s) and metabolite(s) thereof;-   (iii) antipsychotics including for example amisulpride,    aripiprazole, asenapine, benzisoxidil, bifeprunox, carbamazepine,    clozapine, chlorpromazine, debenzapine, divalproex, duloxetine,    eszopiclone, haloperidol, iloperidone, lamotrigine, loxapine,    mesoridazine, olanzapine, paliperidone, perlapine, perphenazine,    phenothiazine, phenylbutylpiperidine, pimozide, prochlorperazine,    risperidone, sertindole, sulpiride, suproclone, suriclone,    thioridazine, trifluoperazine, trimetozine, valproate, valproic    acid, zopiclone, zotepine, ziprasidone and equivalents and    pharmaceutically active isomer(s) and metabolite(s) thereof;-   (iv) anxiolytics including for example alnespirone,    azapirones,benzodiazepines, barbiturates such as adinazolam,    alprazolam, balezepam, bentazepam, bromazepam, brotizolam,    buspirone, clonazepam, clorazepate, chlordiazepoxide, cyprazepam,    diazepam, diphenhydramine, estazolam, fenobam, flunitrazepam,    flurazepam, fosazepam, lorazepam, lormetazepam, meprobamate,    midazolam, nitrazepam, oxazepam, prazepam, quazepam, reclazepam,    tracazolate, trepipam, temazepam, triazolam, uldazepam, zolazepam    and equivalents and pharmaceutically active isomer(s) and    metabolite(s) thereof;-   (v) anticonvulsants including for example carbamazepine, valproate,    lamotrogine, gabapentin and equivalents and pharmaceutically active    isomer(s) and metabolite(s) thereof;-   (vi) Alzheimer's therapies including for example donepezil,    memantine, tacrine and equivalents and pharmaceutically active    isomer(s) and metabolite(s) thereof;-   (vii) Parkinson's therapies including for example deprenyl, L-dopa,    Requip, Mirapex, MAOB inhibitors such as selegine and rasagiline,    comP inhibitors such as Tasmar, A-2 inhibitors, dopamine reuptake    inhibitors, NMDA antagonists, Nicotine agonists, Dopamine agonists    and inhibitors of neuronal nitric oxide synthase and equivalents and    pharmaceutically active isomer(s) and metabolite(s) thereof;-   (viii) migraine therapies including for example almotriptan,    amantadine, bromocriptine, butalbital, cabergoline,    dichloralphenazone, eletriptan, frovatriptan, lisuride, naratriptan,    pergolide, pramipexole, rizatriptan, ropinirole, sumatriptan,    zolmitriptan, zomitriptan, and equivalents and pharmaceutically    active isomer(s) and metabolite(s) thereof;-   (ix) stroke therapies including for example abciximab, activase,    NXY-059, citicoline, crobenetine, desmoteplase,repinotan,    traxoprodil and equivalents and pharmaceutically active isomer(s)    and metabolite(s) thereof,-   (x) urinary incontinence therapies including for example    darafenacin, falvoxate, oxybutynin, propiverine, robalzotan,    solifenacin, tolterodine and and equivalents and pharmaceutically    active isomer(s) and metabolite(s) thereof;-   (xi) neuropathic pain therapies including for example gabapentin,    lidoderm, pregablin and equivalents and pharmaceutically active    isomer(s) and metabolite(s) thereof;-   (xii) nociceptive pain therapies such as celecoxib, etoricoxib,    lumiracoxib, rofecoxib, valdecoxib, diclofenac, loxoprofen,    naproxen, paracetamol and equivalents and pharmaceutically active    isomer(s) and metabolite(s) thereof;-   (xiii) insomnia therapies including for example allobarbital,    alonimid, amobarbital, benzoctamine, butabarbital, capuride,    chloral, cloperidone, clorethate, dexclamol, ethchlorvynol,    etomidate, glutethimide, halazepam, hydroxyzine, mecloqualone,    melatonin, mephobarbital, methaqualone, midaflur, nisobamate,    pentobarbital, phenobarbital, propofol, roletamide, triclofos,    secobarbital, zaleplon, zolpidem and equivalents and    pharmaceutically active isomer(s) and metabolite(s) thereof, or-   (xiv) mood stabilizers including for example carbamazepine,    divalproex, gabapentin, lamotrigine, lithium, olanzapine,    quetiapine, valproate, valproic acid, verapamil, and equivalents and    pharmaceutically active isomer(s) and metabolite(s) thereof.

Such combination products employ the compound of this invention withinthe dosage range described herein and the other pharmaceutically activecompound or compounds within approved dosage ranges and/or the dosagedescribed in the publication reference.

Biological Assays

The pharmacological properties of the compounds of the invention can beanalyzed using standard assays for functional activity. Examples ofglutamate receptor assays are well known in the art as described in, forexample, Aramori et al., 1992, Neuron, 8:757; Tanabe et al., 1992,Neuron, 8:169; Miller et al., 1995, J. Neuroscience, 15:6103; Balazs, etal., 1997, J. Neurochemistry, 1997,69:151. The methodology described inthese publications is incorporated herein by reference. Conveniently,the compounds of the invention can be studied by means of an assay thatmeasures the mobilization of intracellular calcium, [Ca²⁺]_(i) in cellsexpressing mGluR2.

hERG activity was assessed using the process described byBridgland-Taylor, M. H., et al, J. Pharm. Tox. Methods 54 (2006)189-199.

Solubility was determined in pH 7.4 phosphate buffer after equilibrationfor 24 h at 25° C. and HPLC-UV and LC-MSMS were used for quantitation.

A [³⁵S]-GTPγS binding assay was used to functionally assay mGluR2receptor activation. The allosteric activator activity of compounds atthe human mGluR2 receptor were measured using a [³⁵S]-GTPγS bindingassay with membranes prepared from CHO cells that stably express thehuman mGluR2. The assay is based upon the principle that agonists bindto G-protein coupled receptors to stimulate GDP-GTP exchange at theG-protein. Since [³⁵S]-GTPγS is a non-hydrolyzable GTP analog, it can beused to provide an index of GDP-GTP exchange and, thus, receptoractivation. The GTPγS binding assay therefore provides a quantitativemeasure of receptor activation.

Membranes were prepared from CHO cells stably transfected with humanmGluR2. Membranes (30 82 g protein) were incubated with test compound (3nM to 300 μM) for 15 minutes at room temperature prior to the additionof 1 μM glutamate, and incubated for 30 min at 30° C. in 500 μl assaybuffer (20 mM HEPES, 100 mM NaCl, 10 mM MgCl₂), containing 30 μM GDP and0.1 nM [³⁵S]-GTPγS (1250 Ci/mmol). Reactions were carried out intriplicate in 2 ml polypropylene 96-well plates. Reactions wereterminated by vacuum filtration using a Packard 96-well harvester andUnifilter-96, GF/B filter microplates. The filter plates were washed4×1.5 ml with ice-cold wash buffer (10 mM sodium phosphate buffer, pH7.4). The filter plates were dried and 35 μl of scintillation fluid(Microscint 20) was added to each well. The amount of radioactivitybound was determined by counting plates on the Packard TopCount. Datawas analyzed using GraphPad Prism, and EC₅₀ and E_(max) values (relativeto the maximum glutamate effect) were calculated using non-linearregression.

As illustrated in Table 2, below, generally, compounds described hereinhave favourable solubility, low capacity to activate the hERG ionchannel and were highly active in assays described herein for mGluR2modulator activity, having EC₅₀ values as shown.

TABLE 2 Hu GTPgS Example Hu GTPgS Median Top Solubility hERG Mean No.EC50 (nM) Effect (%) (μM) IC50 (M) 1 64 127 33.4 >3.30E−05 2 600 1146.82 2.10E−05 3 214 117 21.4 >3.30E−05 4 150 130 9.53 >3.30E−05 5 425 6719.2 >3.30E−05 6 510 110 17.5 2.30E−05 7 230 139 16.6 >3.30E−05 8 115123 31.1 >3.30E−05 9 37 101 3.57 >3.30E−05 10 618 103 54.1 >3.30E−05 1166 114 4.35 >3.30E−05 12 36 100 11.2 >3.30E−05 13 479 78 153 >3.30E−0514 60 97 3.53 1.90E−05 15 530 100 66.3 >3.30E−05 16 664 79 435 >3.30E−0517 84 139 15.5 >3.30E−05 18 56 109 4.65 >3.30E−05 19 443 141273 >3.30E−05 20 85 122 5.74 >3.30E−05 21 514 106 9.32 >3.30E−05

1. A compound that is5-[7-chloro-((S)-1-cyclopropyl-ethyl)-1-oxo-2,3-dihydro-1H-isoindol-5-yl]-isoxazole-3-carboxylicacid dimethylamide or a pharmaceutically acceptable salt thereof.
 2. Acompound according to claim 1 in the form of a pharmaceuticallyacceptable salt.
 3. A pharmaceutically acceptable salt according toclaim 2 wherein said salt is a hydrochloride, a hydrobromide, aphosphate, an acetate, a fumarate, a maleate, a tartrate, a citrate, amethanesulphonate or a p-toluenesulphonate.
 4. A method of making acompound according to claim 1, comprising: converting a 4-bromo-anilineto a corresponding nitrile under Sandmeyer reaction conditions;converting the nitrile to an amide by hydrolysing with a base;diazotizing the amide and then hydrolysing with nitrososulphuric acid toprovide a benzoic acid; protecting the benzioc acid as a methyl ester;monobrominating the benzylic methyl group with N-bromosuccinimide usingbenzoyl peroxide as the radical initiator to yield 6-substituted4-bromo-2-bromomethyl-benzoic acid methyl ester; cyclizing the6-substituted 4-bromo-2-bromomethyl-benzoic acid methyl ester to an4-bromo isoindolone with an amine; reacting the 4-bromo-isoindoloneunder Sonagashira conditions with a protected acetylene; deprotectingthe acetylene with a base; reacting the deprotected acetylene with ethyl2-chloro-2-(hydroxyimino)acetate to generate an isoxazole ester, andhydrolysing the ester to the acid and amidating usingisobutylchloroformate and N-methyl morpholine and an appropriate amineto generate an amide of Formula I, or, generating an amide of Formula Ifrom an isoxazole ester by reaction with an amine and heating.
 5. Apharmaceutical composition comprising a compound or a pharmaceuticallyacceptable salt thereof according to claim 1 and at least onepharmaceutically acceptable carrier or excipient.
 6. A method for thetreatment or prevention of neurological and psychiatric disordersassociated with glutamate dysfunction in an animal in need of suchtreatment, comprising the step of administering to said animal atherapeutically effective amount of a compound or a pharmaceuticallyacceptable salt thereof according to claim
 1. 7. A method for thetreatment or prevention of neurological and psychiatric disordersassociated with glutamate dysfunction in an animal in need of suchtreatment, comprising the step of administering to said animal atherapeutically effective amount of a pharmaceutical compositionaccording to claim
 5. 8. A method according to claim 7, wherein thedisorder is schizophrenia or anxiety.
 9. A method of treatingschizophrenia or anxiety in a subject in need of such treatment,comprising the step of administering to said subject a therapeuticallyeffective amount of a compound or a pharmaceutically acceptable saltthereof according to claim
 1. 10. A method of treating schizophrenia oranxiety in a subject in need of such treatment, comprising the step ofadministering to said subject a therapeutically effective amount of apharmaceutical composition according to claim 5.